$root_x509 = Crypt::OpenSSL::X509->new_from_string(
    $root_key_data, FORMAT_ASN1
);
 $root_key = Crypt::OpenSSL::RSA->new_public_key(
    $x509->pubkey()
);  

 $other_x509 = Crypt::OpenSSL::X509->new_from_string(
    $other_key_data, FORMAT_ASN1
);
 $other_key = Crypt::OpenSSL::RSA->new_public_key(
    $x509->pubkey()
);